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Latest revision as of 06:35, 2 February 2022
| ML20217E550 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 03/26/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20217E484 | List: |
| References | |
| 50-454-97-21, NUDOCS 9803310073 | |
| Download: ML20217E550 (21) | |
See also: IR 05000454/1997021
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U.S. NUCLEAR REGULATORY COMMISSION l
REGIONlli
Docket No: 50-454
License No: NPF-37
Report No: 50-454/97021(DRS)
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Licensee: Commonwealth Edison Company
Facility: Byron Nuclear Power Station Unit 1
Location: 4448 N. German Church Road
l Byron, IL 61010
Dates: September 19,1997 - February 26,1998
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, inspectors: J. Schapker, Reactor Engineer
l M. Holmberg, Reactor Engineer
! R. Bailey, Reactor Engineer l'
B. Metrow, IDNS
L. Sage, IDNS 1
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Approved by: J. A. Gavula, Chief
Engineering Specialists Branch 1
Division of Reactor Safety
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9903310073 900326
PDR ADOCK 05000454
G PDR
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EXECUTIVE SUMMARY
Byron Nuclear Power Plant, Unit 1
NRC Inspection Report 50-454/97021
This inspection included observations of operations training, preparation for steam generator
l replacement, maintenance / construction activities, and review of the engineering and quality
l assurance efforts completed for the steam generator replacement modification for Unit 1.
Ooerations
.
Operator training and procedure revision for the steam generator replacement appeared
to be thorough and conservative. ( Section 05.1)
Maintenance
,
.
Overall steam generator (SG) preparation for the replacement project demonstrated
l good engineering; construction / maintenance efforts focused on safety. Repairs to the
SG tube bundle "J" tabs were accomplished with conservative procedures for safety,
prevention of foreign material being left in the secondary side of the SG, and repair
processes. Although the repairs were accomplished per the Babcock and Wilcox
i Intemational (BWI) specifications, there appeared to be some probability that some
l tubes could be in contact within the SG. Verification of tube positioning in the installed
l
position was planned for the first refueling outage. (Section M1.1)
.
The extensive use of mock-ups for training was a significant asset in providing
assurance of craft proficiency in the implementation of the special processes,
particularly for the welding of reactor coolant system loop piping to SG reactor coolant
nozzles, and the containment restoration. (Section M.1.1)
i
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. The licensee replacement program and implementation met the ASME Section lli and
XI requirements. Class 1 primary coolant system (narrow groove) welding was
accomplished with only minor deviations, resulting in essentially flaw free welds.
Preparation of these weld surfaces for preservice and inservice examination was
prepared well which enabled complete ASME code coverage of the welds using
ultrasonic examination. However, SG feedwater field welds and main steam field welds
l required numerous repairs; difficulty in maintaining a consistent root resulted in
! excessive root geometry in some weld joints. (Section M1.2)
'
. A violation of NRC requirements was identified during observation of a liquid penetrant
examination of a reactor coolant loop pipe to SG nozzle weld. (Section M1.2)
i
. The removal and replacement of concrete, rebar, and tendon sheathing for the steam
generator containment access were accomplished in a proficient and well-planned effort.
However, horizontal tendon replacement encountered major difficulties causing damage
to the tendon sheathing. (Section M1.3)
I
. Inservice inspection program, procedures, and examinations observed met the
applicable ASME Code and regulatory requirements. (M1.5) )
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REPORT DETAILS
1. Onorations
05 Operator Training and Qualification
05.1 Steam Generator Reolacement Trainina (Unit 1)
a. Insoection Scoce (50001)
The inspectors conducted a review of training for steam generator replacement activities
for licensed operators. Additionally, the inspectors looked at post modification activities
which included training on drawing updates, procedure changes, and resolution of
outstanding issues, j
b. Observations and Findinas
The inspectors observed licensed operator training conducted in the plant specific i
control room simulator on September 22,1997. A scenario drill guide containing a 1
design basis Steam Generator Tube Rupture (SGTR) event was used to record each
individual operator response and the time to complete that response during the
evaluation of two operating crews. Each operating crew was expected to respond to a
500 gallon-per-minute SGTR in one SG and implement the appropriate operating or l
emergency operations procedures to address the loss of inventory. One of the two
crews evaluated did not meet the analyzed time requirements and was successfully
remediated.
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The inspectors conducted a review of all applicable operating procedures which
addressed a normal plant startup or shutdown evolution, a steam generator tube leak, or
a SGTR event. Included in that review was an observation of licensed operator
classroom training during the presentation of "SG Replacement Procedure Changes
Overview" lesson plan. The instructor appropriately highlighted operational differences
and procedural changes which affected operator response. The inspectors also ,
reviewed the design basis change document for the plant specific simulator. No
deficiencies or concerns were noted by the inspectors.
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c. Conclusions
Licensed operator training staff conducted appropriate classroom training and simulator ,
evaluation to reinforce a recent pir.nt modification and related procedure changes. l
Improper operator response during simulator training was promptly identified and
corrected to ensure continued safe operations.
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11 . Maintenance 1
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M1 Conduct of Maintenance
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, M1.1 Observations of Reolacement Steam Generator (RSG) Preoaration Activities
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a. Insoection Scoce (50001) l
Review of Welding Procedure Specifications (WPS), Procedure Qualification Records I
(POR), Nondestructive Examination procedures (NDE), certification of qualification of
examiners, inspectors, welders, and welding operators. l
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l Observations of in-process work activities including:
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- Welder and welding operator qualifications. ;
.
Welder training including training on mock-ups of reactor coolant loop (RCL)
piping to SG Nozzle. ,
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Mock-up training installation of rebar, tendon s%athing, welding of containment
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liner, concrete placement of the containment rfening, and containment opening
concrete removal.
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Repairs to the SG "J" tabs which support f,G t. bing in the outer periphery in the
l U-bend area of the tube bundle.
.
Welding activities on the SG feedwate: nozzle-to-elbow and pipe-to-elbow welds,
j and shop-fabricated SG feedwater p' ping.
. Radiography, liquid penetrant, an ultrasonic examination of the SG feedwater
l nozzle-to-elbow welds.
.
Review of the base line eddy current examination data for the replacement SG
j tubes.
l b. ObservatiQDs and Findings
b.1 Welder Qualifications
The inspector observed welders and welding operators performing qualification coupons
as required by ASME Code Section IX requirements. Tne welder's qualification
coupons were inspected for appropriate identification, proper positioning,' weld material
control, welding in progress, and testing of coupons. WPS were reviewed to the
referenced POR for proper application of the welding essential and supplemental
variables.
Mock up training using procedures, equipment, and personnel to be utilized for the
special processes was observed.
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A full scale mock-up was made for the containment opening (the containment
opening was made by cutting a hole into the reinforced concrete containment
wall). The mock-up included: removal and placement of containment concrete,
cutting and replacement of the containment liner plate, and replacement of rebar
and tendon sheathing. Observations of the mock-up processes verified the
adequacy of the procedures to be used for the containment opening and closure.
.
Machine welded narrow groove SG Nozzle to RCL piping mock-ups were made
to provide training for the welding operators. Observations of the mock-up
demonstration by the inspectors verified the adequacy of the processes and
welding operator's performance.
b.2 Correction of SG Fabrication Errors
The SG fabricator, Babecck and Wilcox International (BWI), identified a fabrication error
for the installation of "J" tabs, which provide support for the outer row of SG tubes.
(Some of the "J" tabs were improperly installed causing tube-to-tube contact.) BWI
developed repair and inspection procedures to fix the fabrication errors.
The inspector observed the "J" tab repairs performed by BWI. Repairs were made
on-site for SG-A and SG-B (SG-C and D were repaired prior to shipping from the
vendor). The inspector attended the confined space and foreign material exclusion
(FME) training, observed "J" tab weld removal, tube and "J" tab adjustment, tack
welding of "J" tabs, observed FME practices, and inspected the SG-A tube bundle
periphery for tube contact upon completion of the repair. The inspector identified one ,
tube in contact with a lower row tube on column 36 at the top of the bundle.
'
Discussions with BWI engineering concluded that the contact was due to the position of
the SG (horizontal) and once installed in the vertical position the tubes would conform to
the correct position. The tube in question had a unsupported free span which increased
the sagging of the tube in the horizontal position. All of the tubes and supporting "J"
tabs were adjJsted to the correct dimensional tolerance specified by BWI procedures.
Additional eddy current (ET) examination in the horizontal position, on site, confirmed
that sagging of the tube bundle caused contact on some of the tubes. The pattern for
the tubes with contact appeared to reflect the orientation of the position of the SG in the
horizontal position (the lower section assumed the most tubes with contact) after
rotation of the SG. The tube bundle has non-rigid design tube supports (egg crate)
which sag due to gravity in the horizontal position. BWI performed a visual examination
of the secondary side internals after installation of the RSGs, and did not find any of the
tubes in contact. The licensee contacted other utilities who have installed and operated
this model of SG. Eddy current examination of the other utilities' SGs confirmed that the
tubes assumed the correct spacing once in the installed position (vertical).
The inspector reviewed the vendor's ET for the base line inspection of the SG tubes, ET l
analyst guideline procedure No. 255743 revision C, and reviewed a sample of ET data l
l including data from the tube-to-tube contact areas discussed above. In addition to the
tube-to-tube contact at the periphery of the tube bundle due to improper positioning of
the "J" tabs, there were indications of tube-to-tube contact or near contact on some of l
the inner rows of tubes. These tube contacts were caused by the sagging tube bundle
while in the horizontal position as discussed above. The licensee plans to perform I
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100% eddy current inspection (bobbin coil) after the first operating cycle, to assure the
tubes are positioned correctly. This is an inspector follow-up item (IFI) 50-454-97021-01
pending verification of the eddy current data during the first refueling outage.
The SG tubes appeared to be of high quality. Dings or dents, manufacturing buff, or
burnishing marks were fewer, and the tube noise appeared less than previously
experienced in current operating SGs. For all four SGs, only one tube was plugged due
to a manufacturing defect,
b.3 BSG Feedwater Pioe Weldina
The inspector observed welding of the SG feedwater shop-fabricated welds, feedwater
elbow to the SG feedwater nozzle, and feedwater piping-to-elbow welds. These welds
were performed prior to installation of the SGs to ease the performance of quality welds
by the accessibility and positioning of the components for welding in the shop and the
SG temporary housing. The inspector verified the WPS were qualified in accordance
with the ASME Section IX Code requirements. Welders performed the welding in
compliance with the weld procedures and nondestructive examinations were performed
as required by the applicable Code requirements. The inspector reviewed the
radiographs (RT), observed liquid penetrant (LPT) and ultrasonic examination (UT)
performed on the first weld and a sample of the remaining welds. The first weld
performed on (SG A) nozzle-to-elbow had a slag inclusion in excess of Code allowable.
The RT contractor correctly identified and dispositioned the anomaly. The slag inclusion
was removed and subsequent repairs were acceptable. The inspector observed the
removal of the slag, repair welding, LPT, and reviewed the final RT film of the weld.
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c. Conclusion l
The NRC concluded that SG preparation for replacement was conservative. The use of
construction and fabrication mock-ups demonstrated a positive commitment to assure
adequate procedures and training of the construction staff. Welding performed on the !
SGs prior to installation met the applicable ASME Code and procedure requirements.
l The "J" tab repairs appeared to be successful; procedural controls of work processes, ;
including maintaining cleanliness, safety and FME, were diligently implemented. The
licensee was planning eddy current inspections to verify the tube bundle was properly
positioned (tubes are not in contact) after one cycle of operation. This inspection was to
be in addition to the normal steam generator inspection required by Technical
Specifications, and would follow the EPRI guidelines for inspections of replacement
SGs. Welder qualifications were performed in accordance with ASME Section IX Code
'
requirements.
M1.2 Observation of Steam Generator Replacement Activities
M1.2.1 Reactor Coolant Looo System (RCS), Feedwater (FWL Main Steam (MS) Pioino
a. Insoection Scoce (73753. 50001)
Inspectors observed weld operators performing machine gas tungsten arc welding
(GTAW) of the RCS to install replacement steam generators (RSGs) A, B, C, and D for
engineering change notice BYR 000764M under dulgn control package 9500394.
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Inspectors observed welding performed for the RSG feedwater and main steam piping
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reinstallation and modification.
inspectors reviewed weld procedures, work packages, weld material control, and weld
operator qualification records for the welding that was observed.
Inspectors observed liquid penetrant examination, and reviewed ultrasonic examination
and radiographs of the primary steam generator nozzles to RCS Loop piping welds,
b. Observations and Findings
A semiautomatic pulsed arc GTAW welding process was used in the RCS welding of the
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RSGs. For the RCS welds, a reduced angle or narrow gap weld joint design was used,
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Inspectors observed the weld operators performing outside and inside diameter welds
on the hot leg and crossover elbow for RSGs A, B, C, and D. No discrepancies were
identified and the welding parameters (gas flow rates, primary current settings,
background current settings, travel speed, and weld filler material type) were in
accordance with WPS P8-T(RA) requirements. Weld operators implemented and
l recorded changes in the process welding parameters as required by the WPS for the
root, fill, and weld ccp passes. The inspectors considered the weld operators observed
l- to be knowledgeable of the GTAW equipment settings and process parameters.
SG feedwater and main steam piping welding complied with the essential variables and
procedure requirements of (WPS) P1-AT-LH(CVN+35R/0) and P1-T(CVN+35R/0)
respectively. However, there were more weld defects detected (radiography) than
would be anticipated for this type of welding. The weld defects were corrected and
examined in accordance with ASME Code and Bechtel procedure requirements.
l
Inspectors reviewed qualification documentation of the welders and weld operators
performing the RSG, feedwater, main steam, and RCS welding. All of the welders and
weld operators had been qualified for the welding processes and had been satisfactorily
l tested by mechanical testing or radiography, as specified in the ASME Code,Section IX,
QW-305. The results of these qualification tests were recorded as satisfactory in the
certification documentation which met Code requirements.
WPS P8-T(RA) Revision 2 used for the RCS welds was qualified in accordance with the
l ASME Code Section IX requirements by supporting documentation recorded in
POR 1041. The inspectors found no deviations from ASME Code,Section IX, QW-256
l Welding Variables Procedure Specifications GTAW," requirements for this WPS and
POR.
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The inspector observed liquid penetrant examination to the SG-A FW-1 hot leg OD.
During the examination process the LPT examiner removed the penetrant and applied
the developer. Before completion of the developer application, the examiner decided
the penetrant had not been adequately removed prior to the application of the
developer, removed the developer, and recleaned the examination area. The LPT
examiner then reapplied the developer and interpreted the results of the examination.
The inspector questioned the adequacy of the examination because the examiner
recleaned the surface and reapplied the developer without repeating the previous steps
required by the ASME Code,Section V. The LPT examiner stated that this action was
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! permitted by the procedure. The inspector's review of the procedure
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(Bechtel-PT(SR)-ASME lil/XI Revision 1) and ASME Code requirements confirmed the
! examination was not completed as required. The licensee's contractor subsequently
l initiated a nonconformance report, and a Lil examiner reexamined the weld in
l accordance with the procedure requirements; no defects were identified. The inspector
determined that the original liquid penetrant examination was not performed in
accordance with ASME Code and applicable procedure requirements, constituting a
violation of 10 CFR 50, Appendix B, Criterion V, which requires that activities affecting
quality shall be prescribed by documented procedures and shall be accomplished in
l accordance with these instructions. (VIO) 50-454-97021-02(DRS)
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Inspectors reviewed the automated "P" scan and manual ultrasonic examination of the
FW-1 welds (SG nozzle to RCS loop piping). Due to the quality of the weld fit-ups and
processing of the OD surface, the licensee was able to obtain full ASME Code
coverage. No indications which exceeded Code allowable were observed. Review of
the radiographs for these welds confirmed sound weld quality.
Inspectors also observed ultrasonic examination and reviewed radiographs for the field
welded SG-FW and MS piping welds. Although the welds observed met the ASME
Code and procedure requirements some had excessive detectable root geometry. The i
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root geometry causes the ultrasonic examination, to be untimely and difficult to interpret.
Future inservice inspection (ISI) examinations required by ASME Section XI
requirements may require significant additional time, and result in additional radiation
dose to the NDE examiners.
c. Conclusions
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Overall licensee RCS welding operations in support of the RSG modification were well-
executed with no significant problems. The machine GTAW on the RCS, manual shield
metal arc welding (SMAW) welds were performed by Code qualified weld operators and
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welders in accordance with ASME Code Section IX qualified procedures. The final weld
surfaces of the RCS welds were exceptionally well-prepared for preservice and inservice
examination, enabling complete ASME Code coverage of the welds, using ultrasonic
examination. The RSG feedwater piping welds with root geometry were acceptable per
ASME Code and procedure requirements. However, the root geometry made the weld
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difficult to inspect with ultrasonic examination.
M1.3 Containment Restoration
a. Insoection Scoce (50001)
Inspectors observed replacement of containment opening rebar, including cadwelding,
installation of tendon sheathing, concrete placement (including testing and consolidation
procedures) and horizontal tendon sheathing removal and repair, due to sheathing
damage during reinstallation of the tendons.
b. . Observations and Findinas
inspectors observed placement of rebar and cadwelding of the replacement rebar.
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Observations of rebar splices 11 A03T,11 A18T,10A06R,10A07L and 10A08L were
! completed by qualified cad welders in accordance with Bechtel procedure CP-C-05
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I revision 2. Destructive testing of " sister" splices was observed by the inspectors.
) Testing was conducted in accordance with an approved procedure in compliance with
l the original construction code. Documentation of testing was accomplished in
accordance with the design input and analysis document section 3.20.3.
l During observations of cadwelding of rebar, the inspector noted construction procedure
CP-C-05, revision 2 was being used by Bechtel Quality Control personnel to record cad
weld variables and document results. Review of the Work Plan and Inspection Record
(WPIR) referenced revision 1 of this procedure. The inspector interviewed the
l document control supervisor who determined that procedure CP-C-05 was revised on
the previous day to revision 2. The inspector noted that although the QC inspector was
using the proper revision of the applicable procedure, this was not updated in the WPIR.
Inspectors observed the placement of the tendon sheathing in the containment opening, l
visually verified application of concrete bonding agent, and concrete form placement.
The tendon sheathing was modified with a tendon grease fitting, to assure tendon voids
were filled with grease. Forms were designed with adequate access to assure
placement of the concrete would flow to all voids. Inspectors observations of concrete
placement verified proper consolidation techniques, concrete placement, inspection, and I
test were accomplished in accordance with Bechtel Specification 23161-C-302(O). The
safety related ready mixed concrete specification "Bechtel 23161-C-311(O) was i
reviewed, and truck batch tickets were verified for required testing and mix design.
Sampling and testing of concrete at delivery point were observed and found to be in
compliance with procedure and referenced American Concrete Institute (ACl)
specifications requirements. Inspectors observed the concrete compressive strength
testing of cylindrical test specimens (seven day) for the lower, middle and upper j
sections of the containment wall restoration. Testing was performed in accordance with l
ASTM C39-94, " Standard Test Method for Compressive Strength of Concrete
Specimens."
Reinstallation of the vertical tendons was without incident, however the horizontal
tendon reinstallations encountered considerable difficulty. Several small access
penetrations in the concrete containment were required to remove tendon sheathing
which had tom loose and bailed up in front of the tendon during reinstallation. The
inspector reviewed the licensee's Engineering Change Notice (ECN)-BYR000749S-02
for the removal of the blockage, repair, and reinstallation of the tendons. The inspector
observed the concrete removal areas; and the sheathing removal. No damage or
cutting of the rebar was identified. The licensee did not intend to replace the tendon
l sheathing removed from the tendon except in the areas of the concrete removal. The
inspector questioned the licensee's proposed repair which excluded the tendon
sheathing. The licensee stated that the tendon sheathings' only function was to act as a
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concrete form for the tendon run.
c. Conclusion'
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Inspections and reviews verified the licensee activities complied with the applicable code
and specification requirements. Observations of the work activities revealed good work
practices and attention to detail. For the tendon replacement without sheathing, the
inspector reviewed the licensees engineering evaluation and contacted NRR for
additional guidance. Conference calls with Region Ill, NRR, and the licensee concluded
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j- that the installation of the tendons without sheathing was not detrimental to the concrete
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or the tendons and therefore in compliance with the specification requirements.
M1.4 Containment Liner Patch Welding
a. Insoection Scone (73753. 50001)
Inspectors observed welders performing SMAW to reinstall the rectangular containment
liner patch removed to support the RSG modification.
Inspectors reviewed weld procedures, work package, and weld operator qualification
records for the welding that was observed.
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b. Observations and Findings
inspectors observed portions of the welding completed on the containment inner liner
vertical welds FW-2 and FW-4. The welders observed were knowledgeable of weld
parameters and maintained weld travel speeds, current, and voltage settings within
ranges allowed by the WPS P1-A-Lh Revision 0. The E-7018 weld rod material used
for the welding observed was properly stored in heated containers to prevent moisture
adsorption (moisture adsorption into the weld rod coating can lead to hydrogen induced i
weld cracking). Additionally, documentation for the weld rod materials checked out by l
welders was readily retrievable at the work site.
The welders observed by inspectors had been qualified to Code requirements by
radiography for the SMAW process, as allowed by ASME Code,Section XI, QW-305.
l The results of these qualification tests were recorded in the certification documentation. l
WPS P1-A-Lh Revision 0, was qualified in accordance with the ASME Code Section IX
requirements by supporting documentation recorded in PQRs 695 and 690. The
inspector found no deviations from ASME Code Section IX QW-253, " Welding Variables
Procedure Specifications SMAW," requirements for this WPS and POR.
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c. Conclusions
l Welding operations observed in support of the reinstallation of the containment liner
l patch were executed as planned with no significant problems. The SMAW of the inside
of the containment liner patch was performed by Code qualified welders in accordance
with Code qualified procedures. Nondestructive examinations of the liner plate welds
were performed in accordance procedure and Code requirements.
M1.5 Inservice insoection
Mi.5.1 Program and Procedure Review
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a. Insoection Scooe (73751: 73052)
Inspectors reviewed the ISI program documents, procedures, including relief requests,
and audit and surveillance documents.
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b. Observations and Findings
The ISI program was conducted in accordance with ASME Section XI,1989 Edition. All
ISI procedures reviewed were found to be in accordance with ASME Code,Section V
and XI,1989 Edition requirements. Where ASME requirements were determined to be
impractical, specific relief requests were submitted to NRR in writing. The licensee
requested relief from ASME Code requirements for the inspection of longitudinal welds
in piping. There was sufficient organizational staff to ensure that acceptable ISI work
was perfonned.
c. Conclusions
l The inspectors verified that ISI activities were being conducted in accordance with the
appropriate procedures and ISI program. The inspector noted the relief requests were
approved by NRR, properly documented, and incorporated into the ISI program.
M1.5.2 Observations of Isl Work Activities
i
a. Insoection Scone (73753 and 73755)
Inspectors observed ISI exami.,ations and reviewed ISI examination data packages to l
l assure appropriate examination was performed and data was recorded as required by !
l the ASME Code. Qualification of personnel performing NDE work was verified.
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b. Observations and Findings
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The inspectors observed contractor personnel performing NDE on SG Feedwater and
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blowdown piping. NDE personnel were knowledgeable of procedural requirements and
proficient in the performance of NDE. The inspectors found the NDE data packages for
UT and LPT properly reviewed by the licensee and the ANil. UT indications recorded on
i the data sheets were evaluated using additional UT examinations, review of construction
l radiographs, or both. Personnel performing NDE were found to have proper
qualifications which had been reviewed and accepted by the licensee staff and the ANil.
l c. Conclusions
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NDE was performed in accordance with applicable procedures, properly documented, !
by qualified NDE personnel.
M7 Quality Assurance in Maintenance Activities ,
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M7.1 Procurement and Recelot Insoection
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a. Insoection Scooe (73753. 50001) ,
For the RSG modification, inspectors reviewed procurement documentation for i
materials used in support of the RCS welds.
For the RSG "B" feedwater system modification inspectors reviewed procurement
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documentation of safety related materials. ,
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b. Observations and Findings
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b.1 RCS Weld Filler Material Procurement CentroHed
Receipt inspection records reviewed, clearly established that filler material on the GTAW
, machine spool W-009 used in the SG A hot leg RCS weld, and spool W-006 used on the
l SG D crossover elbow RCS weld, were traceable to the material certifications for
ER 308L weld filler metal.
b.2 Feedwater ASME Code Material Procurement Controlled
Inspectors verified through receipt inspection records that,117 feet of 16-inch diameter
pipe and a 90-degree 16-inch pipe elbow had been procured to ASME Code Section Ill,
Class 2,1974 Edition Summer 1975 addenda and Section ll 1989 Edition standards
from a 10 CFR 50 Appendix B certified supplier. This piping and elbow were used in the
RSG "B" feedwater modification and installed under work request 960106974, " Rework
Feedwater Line for RSG's," Revision 2.
c. Conclusions
Procurement and receipt inspection activities were well-controlled and in accordance
with ASME Code requirements for the RCS weld filler materials and the RSG-B
feedwater system modification work.
M7.2 Control of Nonconforming Conditions
a. Insoection Scoce (73753. 50001)
For the RSG modification, the inspectors reviewed the prime contractor (Bechtel)
nonconformance logs and selected six nonconformance reports (NCRs) for further
review.
b. Observations and Fir' dings
in NCR BY-005, the contractor documented that a SG A feedwater elbow was below the
specified minimum wall dimension at the counterbore and that a compound bevel
existed on the weld preparation surface. The counterbore minimum wall dimension was
restored by performing weld buildup using Code-qualified procedures and a 30-minute
post-weld heat treatment. The weld preparation surface which exceeded the 30-degree
angle was incorporated into the final weld and the affected WPS was updated.
Additionally, the Authorized Nuclear inspector's concurrence had been obtained for this
nonconformance repair affecting an ASME Code elbow. The inspector considered
these actions appropriate and in accordance with ASME Code requirements. ,
1
In NCR BY-007, the contractor documented that a SG B feedwater elbow was below the I
specified minimum wall dimension for a 2-inch radial segment. The licensee accepted
f this nonconformance as is, based on the 12.5 percent under tolerance allowed in the )
ASME Code Material Specifications for the SA 106 piping. Since the minimum wall '
dimension met Code, the inspector considered this action appropriate.
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! In NCR BY-012, the contractor documented that a section of 16-inch diameter schedule
80 safety related piping received from the licensee stock system contained an area that ;
was below minimum wall. The licensee initiated problem identification form B1997- ;
03310 to document the condition and then removed and scrapped the affected section
of this schedule 80 piping. Additionally, the licensee performed ultrasonic thickness
measurements of all piping with the same heat number and all other piping was found to ,
be within specifications. The licensee considered this an isolated incident which !
occurred in the fabrication process. The inspector considered this NCR as illustrative of
an effective contractor receipt inspection process,
in NCR BY-013, contractor quality control personnel documented that a welding
subcontractor (PCI Energy Services) had 12 items (e.g. WD-40 , Elmers glue, ,
Locktite )in equipment and gang storage boxes that were not on the Bechtel approved I
products use list for the site. Corrective actions included retraining on-site personnel
and notifying subcontractors of Bechtel's consumable control requirements. The
inspector considered this NCR to illustrate good contractor oversight of subcontractors. 3
in NCR BY-033, the contractor documented that liquid penetrant examinations revealed
indications on the SG A hot and cold leg nozzle-to-safeend welds following machining ;
and grinding operations. These surface indications were ground out, weld repaired, and '
the welds accepted based on final NDE. The inspectors considered these contractor
corrective actions in conformance with ASME Code requirements. An inspector
observed the final NDE performed on this repair, which was accomplished in
accordance with applicable procedure and Code requirements,
in NCR BY-040, the contractor had documented that for welds completed on main
steam SG-A piping and feedwater SG-A, C and D piping, that welding parameters
(travel speed, voltage or amperage) had not been maintained within the limits specified
by the applicable WPSs. The welding parameters that were outside the WPS specified
ranges are considered nonessential variables by the ASME Code Section IX for the
SMAW process. These deficiencies were identified by the ANI. The welds affected were
accepted "use-as-is" based on a comparison of the heat inputs resulting from the as-
welded parameters with and the maximum heat input demonstrated in the applicable
PORs. The disposition of these welds to "use-as-is" was acceptable to the inspectors,
since the welding as performed maintained the essentia! and supplemental variables for
the welding process as demonstrated in the supporting PORs. Corrective actions
included revision of several of the procedures for impact tested welds. Additional
training of the welding supervisors and documentation reviewers to assure the WPS
welding parameters were adhered to, and documentation review was performed
thoroughly as required by procedures.
c. Conclusions
Overall the RSG modification prime contractor (Bechtel) receipt inspection and quality
,
controls were considered effective by the inspectors as evidenced by the number and
l
types of issues identified and corrected in the nonconformance reports. The corrective
f actions met Code requirements and demonstrated good technical judgement.
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E8 Miscellaneous Engineering issues (92903)
E8.1 (Closed) VIO 50-454/97013-01(a): failure to evaluate the impact of the replacement
steam generator modification on the residual heat removal (RHR) system.
The inspectors reviewed licensee corrective actions completed for this issue, which
included revising the RSG modification safety analysis to describe the impact on the
RHR system design basis cooldown performance. The RSG modification caused an
additional 0.3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> increase in plant cooldown time, however, the overall time was still
within the original 36.0 hour0 days <br />0 hours <br />0 weeks <br />0 months <br /> system design basis. This item is closed.
E8.2 (Closed) VIO 50-454/97013-01(b): failure to evaluate the impact of the RSG
modification on containment sump and pH levels in a main feed line break (MFLB) and
main steam line break (MSLB) accident. The inspectors reviewed corrective actions
completed for this issue, which included evaluation of the containment sump level and
pH levels for an MFLB and MSLB with the RSGs. The licensee revised RSG safety
evaluation concluded that containment sump level and pH were bounded by other
accident analysis for the RSG and therefore acceptable. However, the licensee
concluded that the containment spray system would actuate in the event of an MFLB
with the RSG, which did not occur with the original steam generators. The licensee
initiated UFSAR updates to describe this change in plant response. This item is closed.
E8.3 (Closed) URI 50-454/97013-02(DRS): Technical Specification (TS) 3.7.1.3 and
minimum condensate storage Tank (CST) inventory safety evaluation conclusions
potentially inadequate for the RSG.
The inspectors had identified deficiencies in the supporting design basis cooldown heat
load calculation for the RSG, which had been used as a basis for safety evaluation !
conclusions pertaining to the minimum inventory requirements for the condensate l
storage tank. The licensee subsequently issued Revision 2 to FTl calculation l
32-1266253-02 "RSG/OSG [ original steam generator] AFW [ auxiliary feedwater] l
cooldown requirements." This calculation demonstrated that the minimum CST ,
inventory identified in the UFSAR wou!d be adequate for the RSGs. Additionally, the j
inspectors had identified a concern for the adequacy of TS 3.7.1.3 minimum CST leve! ,
of 40 percent (200,000 gallons), which did not include additional margins for instrument i
inaccuracy and vortexing effects above the UFSAR minimum inventory of 200,000 l
gallons. As a corrective action for a prior violation (50-454/97015-04a(DRP); !
50-455/97015-04a(DRP)), the licensee submitted a change to TS on December 30, ;
1997, which included a change to TS 3.7.1.3 that increased the required minimum level
for the Unit 1 CST to 60 percent. The increased minimum CST levelincluded inventory
margins which accounted for instrument error and vortexing effects. Thus, the
inspectors had no further concems with the adequacy of this TS. This item is closed.
1
E8.4 (Closed) IFl 50-454/97013-04: review of actualloop flowrates to verify mechanical
design flow margin. The inspectors had identified a concem pertaining to the small
l margin between the reactor coolant system (RCS) mechanical design fiow (MDF) and i
f the RCS best estimated flow (BEF) for the RSG modification. An analysis (" Evaluation
of increased Mechanical Design Flow," Revision 1, dated November 26,1997) was
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completed by Westinghouse that demonstrated acceptability of a higher MDF which
resulted in an increased RCS flow margin with respect to the BEF. Thus, the inspectors
had no further concem for the RCS flow margin and this item is closed.
E8.4 (Closed) VIO 50-454/97013-06(a): design basis RCS volume miscalculated / misapplied
effecting other RSG analysis.
Inspectors reviewed corrective actions completed for this issue which included revising
calculation BWI 222-7720-A13 and evaluating or correcting all calculations using the
incorrect RCS volume. These corrective actions were considered adequate and this
item is closed.
E8.5 (Closed) VIO 50-454/97013-06(b): design basis inputs missed or nonconservative for
CST minimum inventory calculation.
The inspectors reviewed corrective actions completed for this issue, which included
revising calculation 32-1266253-02 "MG/OSG [ ORIGINAL steam generator] AFW
[ auxiliary feedwater) cooldown requirements," Revision 2. This calculation addressed
each of the deficiencies with the original superseded calculation 51-1266158-01 and
demonstrated that the minimum CST inventory identified in the UFSAR would be
adequate for the RSG modification. This item is closed.
E8.6 (Closed) URI 50-454/97013-07: MSLB analysis inputs appear nonconservative,
inspectors had identified a concern that input values (main steam line flow restrictor
cross sectional area and RSG tube surface area) to the MSLB analysis were potentially
nonconservative. The inspectors reviewed a letter from Babcock and Wilcox Industrics
(dated December 17,1997) to the licensee, which addressed this concern. Specifically,
an additional calculational conservatism in secondary RSG mass (six percent of the
narrow range RSG level) bound the relatively small potential nonconservatisms in the
other input values. This item is closed.
V. Manaaement Meetings
X1 Exit Meeting Summary
The inspectors presented the inspection results to mcmbers of licensee management at the
conclusion of the inspection on February 20,1998. The licensee acknowledged the findings
presented and did not identify any of the potential report input discussed as proprietary.
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PARTIAL LIST OF PERSONS CONTACTED
Commonwealth Edison
K. Kofron, Station Manager
B. Moravec, Steam Generator Replacement (SGR) Site Project Manager
D. Shamblin, SGR Project Manager
M. Leutloff, Byron SGR Project Engineer
D. Wozniak, Byron Station Engineering Manager
D. Rogowski, SGR Project Engineer
T. Schuster, Quality Assurance Manager
P. O'Neill, SGR Quality Supervisor
R. Goetzke, SGR Mechanical Engineer
R. Colglazer, NRC Coordinator
S. Mullins, Braidwood SGR Project Engineer
M. Inserra, SGR Engineer
H. Kim, Pressurized Water Reactor Analysis Supervisor
M. Lesniak, Nuclear Licensing
S. Eich, SGR instrument and Controls Engineer
T. Green, SMAD Level lll
Bechtel
R. Strohman, Project QA Manager
C. Weaver, Project Manager
NELG
N. Hilton, Resident inspector
T. Tongue, Project Engineer
INSPECTION PROCEDURES USED
IP 50001 STEAM GENERATOR REPLACEMENT INSPECTION
IP 73753 INSERVICE INSPECTION
IP 37700 DESIGN CHANGES AND MODIFICATIONS
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ITEMS OPENED, CLOSED OR DISCUSSED
ORfta
IFl 50-454/97021-01(DRS) RSG tube-to-tube contact prior to installation.
VIO 50-454/97021-02(DRS) Failure to perform liquid penetrant examination in
accordance to ASME Code and procedure requirements.
Closed
VIO 50-454/97013-01(a)(DRS) Failure to evaluate the impact of the RSG modification on
the RHR system .
VIO 50-454/97013-01(b)(DRS) Failure to evaluate the impact of the RSG modification on
containment sump and pH levels in a MFLB and MSLB
accident (Section E2.1).
URI 50-454/97013-02(DRS) TS 3.7.1.3 and minimum CST inventory safety evaluation
conclusions potentially inadequate for the RSG (Section
E2.1).
IFl 50-454/97013-04(DRS) Review of actualloop flowrates to verify mechanical
design flow margins (Section E2.1).
VIO 50-454/97013-06a(DRS) Design basis RCS volume miscalculated / misapplied
effecting other RSG analysis (Section E3.2).
VIO 50-454/97013-06b(DRS) Design basis inputs missed or nonconservative for CST
minimum inventory calculation (Section E3.2).
URI 50-454/97013-07(DR'S) MSLB analysis inputs appear nonconservative
(Section E3.2).
Discussed
None
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LIST OF DOCUMENTS REVIEWED
Safety evaluation 6H-97-0047 for design control package 9500394 " Steam Generator
Replacement Modifications."
" Addendum to the Overpressure Protection Report for Byron /Braidwood Nuclear Power Plant
Units 1." Revision 0.
Procedure Date Revision Title
l NDT-C-72 1/97 23 Preservice and Inservice Ultrasonic Inspection of Similar
NDT-C-5 7/96 3 Ultrasonic Examination of Vessel Welds Greater Than 2"
Thick.
NDT-C-40 11/96 4 Preservice and inservice Ultrasonic Examination of
Dissimilar Metal SafeEnd To Nozzle Welds With Iconel
182 Butterhg and Filler Metal.
NDT-C-53 11/96 1 Ultrasonic Examination of Reactor Coolant Pump
Flywheels at PWR Stations.
NDT-C-55 9/69 1 Ultrasonic Inspection of Welds Using Refracted
Longitudinal Wave Techniques.
NDT-C-59 9/69 1 Ultrasonic Examination of the Pressurizer Safety Reliefs,
and Spray Nozzle inside Radius Section at Braidwood and
Byron Stations.
NDT-C-63 7/97 1 Referencing, Stamping, and Surface Preparation
Procedure When Performing LPT, MT, and UT.
NDT-C-67 2/97 0 Ultrasonic Examination of Weld-O-Let Type Brand
Connections at Braidwood and Byron Stations.
NDT-C-72 7/97 0 Ultrasonic Examination of Unit 1 RSG Main Feedwater.
Nozzle Transition Ring Welds at Braidwood and Byron.
Comed-UT- 11/97 0 Automated Ultrasonic Examination of RHR Heat
89-P2 Exchanger Nozzle Welds.
ECN BYR000763M SG Vessel Replacement.
ECN BYR000764M Primary Piping.
! ECN BYR000767M FW Piping (Inside Containment).
ECN BYR000786S Upper Lateral and Lower Lateral Restraint Design.
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FTl document No. 51-1257351-01 "CDS /OSG /RSG Design Transient Comparison."
FTl calculation 51- 1266158-01, "RSG AFW Cooldown Requirements," Revision 1.
FTl calculation 32-1239262-0 !, " Comed LOFW," Revision 1.
NED-1-EIC-0008, " Reactor Coolant Flow Channel Error Analysis," Revision 1
l BYR-96-275," Steam Generator Wide Range Level Indication Error Analysis," Revision 1.
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6lC-1-FW-001, " Steam Generator Narrow Range Level Transmitter Scaling," Revision 1. .
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20/6lC-1-FW008, Unit 1 Steam Generator Narrow Range Level Channel Error Analysis (Steam
Generator Replacement Project)," Revision 1. j
BYR-97-273 " Condensate Storage Tank Level Error Analysis," Revision O.
WPSs P8-T(RA), Revision 2, S3(A588), P1-A-Lh, Revision 0, P1-A-Lh, Revision 0,
1 PQRs 1041,751.
Work permit and inspection record (WP&lR) P-RCA-255 " Severance, Weld Prep, and '
Reconnection of RCS Piping for S.G. A."
WP&lR P-RCB-258 " Severance, Weld Prep, and Reconnection of RCS Piping for S.G. B."
WP&lR P-RCD-264 " Severance, Weld Prep, and Reconnection of RCS Piping for S.G. D."
WP&lR C-CLP-203 " Remove / Reinstall Containment Liner Patch."
WP & IR P-TMP-271 " Installation and Removal of Temporary Air and Argon Systems."
" Welder Performance Qualification Test Record" for Arthur Webber, Jose Vicente, Terry
English, Larry Dickman, Robert Palmer, Joseph Ryder, Larry Underwood, Robert Behrends,
Gene L. Ebert, David Sadnick.
,
NCRs BY-005, BY-007, BY-012, BY-013, BY-033, BY-040, BY-071.
Purchase Order 354700 dated July 30,1997 and Letter from L. Watson of BOC Gases to R.
McKinley of Commonwealth Edison Company dated July 29,1997.
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BOC Gases Liquid / Bulk Gas Shipping Orders; F 416696, F 492512 6, F 554600 4.
Work Request 960106974 " Rework feedwater Line for Replacement SG's," Revision 2.
WP & 1R P-FWB-248A Piping Fabrication / Installation Data Sheet.
Consolidated Power Supply Materials Certification Records for purchase order 503159.
Byron Material Receiving Reports for Job 23161.
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Special Processes Manual For Byron /Braidwood Power Plants (Bechtel) Revision 5.
Technical Specification for Purchase of Safety Related Ready-Mixed Concrete for
Byron /Braidwood Unit 1 Steam Generator Replacement Project Revision 0.
ECN BYR000749-02, Design Change No. 9500389.
Eddy Current Guidelines For The Evaluation of Tubing For Commonwealth Edison
l Replacement Steam Generators No. 255743 revision C. (Babcock & Wilcox Canada)
l Bechtel liquid penetrant examination procedure - PT(SR)-ASME lil/XI Revision 1
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LIST OF ACRONYMS USED
l ANI Authorized Nuclear Inspector
ANil Authorized Nuclear Inservice Inspector
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ASME American Society of Mechanical Engineers
BWI Babcock and Wilcox International
!
CDS Certified Design Specification
! CST Condensate Storage Tank
DCP(s) Design Control Package (s)
ECN(s) Engineering Change Notice (s)
FTl Framatome Technologies International
'
GTAW Gas Tungsten ArcWelding
IFl Inspection Follow up Item
ISI Inservice inspection
LBLOCA Large Break Loss of Coolant Accident
LPT Liquid Penetrant Examination
MFLB Main Feedline Break
MSLB Main Steamline Break
NDE Nondestructive Examination
l NSS Nuclear Steam Supplier
OSG(s) Original Steam Generator (s)
PlF Problem identification Form
POR Procedure Qualification Records
RCL Reactor Coolant Loop
RSG(s) Replacement Steam Generator (s)
SFR Secondary Flow Restrictor ,
SG Steam Generator , I
SGTR Steam Generator Tube Rupture
SMAW Shielded Metal Arc Welding
TS Technical Specification
UFSAR Updated Final Safety Analysis Report
URI Unresolved item
UT Ultrasonic Examination
VIO Violation
WPS Welding Procedure Specification
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